While it is clear that lifespan was extended during human evolution, there is remarkably little data available to assess the specific ways by which this remarkable change in life history came about. This missing information could importantly inform the understanding of how modern lifestyles, in interaction with our evolved biology, produce the health outcomes observed in developed countries. A major limitation at present is a dearth of data on the aging process in humans' closest evolutionary relative, the chimpanzee. The current study would be the first to gather comprehensive data on aging in wild chimpanzees, whose health has not been manipulated by humans during captive management or biomedical experimentation. Like humans during most of their evolutionary history, wild chimpanzees experience frequent nutritional stress and high rates of infectious disease and these processes - little studied in modern aging research - are expected to have shaped species-normative life history strategies. The project entails non-invasive collection of urine and feces from approximately 245 wild chimpanzees (Pan troglodytes) for a broad range of health biomarkers, in additional to observational research for observed morbidity, locomotor proficiency, and social behavior. New data collection will complement and extend existing long-term demographic data, as well as individual histories of social interaction and reproductive effort. The wild data will be supplemented by additional blood-based biomarkers obtained during routine veterinary immobilizations of approximately 240 semi-free ranging chimpanzees in African sanctuaries. The project integrates investigators from major studies of health and aging in human foraging populations, and the central aim (1) of the project is to perform structured comparisons of health and aging between humans and chimpanzees. To further this goal, the additional project aims focus on key variables that are expected to shape senescence, and which are associated with prominent behavioral differences between species: (2) sex differences and the allocation of reproductive effort across the life history, (3) stability of accss to energy, and (4) social status and support. Information gathered in pursuit of these aims has specific relevance to prominent focuses of human aging research: the gender morbidity-mortality paradox, caloric restriction, and the influences of chronic stress and social subordination.
Modern human aging and mortality patterns result from a combination of our modern lifestyle and our evolved patterns of senescence and repair. While there is excellent information on the former, very little is understood about the processes affecting the evolution of the unusual human lifespan. The current study quantifies aging patterns in wild chimpanzees and incorporates specific comparisons with traditional human populations in order to elucidate key mechanisms of evolutionary change from our ape ancestors.
Showing the most recent 10 out of 13 publications
